How to travel from Zermatt to Klein Matterhorn?

We are planning to visit Klein matterhorn from Interlaken on 21st August. Planning it as a day trip so that we are back to interlaken in the night.

Any advice on how does one travel from zermatt to matterhorn glacier paradie? is this to be done by cable car or is there a train that goes up the mountain? and do we need advance booking of tickets for the same?